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Nov. 18, 1930. M. J. mTTENHousr-z ETAL 1,751,861

RADIO RECEPTION APPARATUS Filed Jan. 14, 1.925 5 Sheets-Sheet l ErOsczr TZMazzren Nov. 18, 1930. M. J. mTrENHousE ET AL 1,781,861

RADIO RECEPTION APPARATUS Filed Jan, 14I 1925 3 Sheets-Sheet 2- zvezzzfors Nov. 18, 1930. M. J. Rrr'rENHousE Erm. 1,73L861 RADIO RECEPT I ON APPARATUS I It', fnv-enfers fg e Myzwm torzzey Patented Nov. 1.931)

PATENT OFFICE MYRON J'. RITTENHOUSE; 0F CLEVELAND, A ND OSCAR V. MAURER, 0F EAST CLEVE- LAND, OHIO; SAII MAURER ASSIGNOR TO SAID RITTENHOUSE RADIO RECEPTION APPARATUS Application led .Tanuary 14, 1925.

This invention relates to signaling apparatus and has for its object the provision of an improved vacuum tube and an improved circuit arrangement for use therewith which shall he superior in range, selectivity, clarity and freedom from re-radiation, whether used for radio reception, radio transmitting or telephone repeating.

A very important object of the tube is the provision of a device which shall render a single regenerator circuit, or so called cop circuit, free from re-radiation and adversely infiuencin .neighboring sets. Another important o ject relative to the tube is the wnprovision of a construction wherein all the tubes shall be the same, substantially without variation and not requiring careful matching or choosing. Other advantages of our invention relate to accuracy of tuning, reduction of distortion, and elimination of stray signals, static, and foreign wave lengths; a system wherein regeneration can be maintained at all frequencies without permitting re-radiation on the antenna circuit; and which can be used in standard equipment with a minimum of alteration, with theresult of making a cheap and simple set a rival of the larger and more complicated equipments in point of accuracy of tuning and clarity of reception.

One of the important features of the invention is the provision of a new expedient for maintainin the mean potential of the control electr e at the desired point, this being effected by maintaining therein an induced electrostatic charge; and a second important feature resides in an arrangement whereby building up of the potential of this electrode is prevented, thus dispensing with 4o the need for grid leaks,or other discharging expedients and preventing the occurrence of any oscillatory f 'd discharge. Our improved tube is usalia both as a detector and as an amplifier, and is further available for amplification both in radio frequency and in audio frequency; although for different specific purposes different constructions differing somewthat in detail features are sometimes found most advantageous.

In the drawings accompanying and form- Sel'ial No. 2,297.

ing a part of this application we have shown certain forms of tubes and certain arrangements of circuits embodying our improvements. Fig. 1 is a perspective view of a preferred form of tube embodying our improvements, the same being complete except for the omission of one-half of the control electrode; Fig. 2 is a perspective View of the socket and additional or C battery; Fig. 3 is a plan view of the elements shown in perspective in Fig, 1; Figs. 4, 5, 6, and 7 are views similar to Fig. 3 showing other arrangements of elements; Fig. 8 is a perspective view of certain of the internal elements illustrated in Fig. 7; Fig. 9 illustrates an- 65 other form of tube embodying the same elements but designed and arranged in a different manner; Fi 10 is a plan view of the element shown in 1g. 9; Figs. 11 and 12 show modified arrangements of the same elements;

Fig. 13 illustrates a single tube cop set provided with our improved tube; Fig. 14 is a diagram of the same system having added thereto two stages of amplification in audio frequency; Fig. 15 is a general diagram showing tive of our improved tubes including two stages of amplification in radio frequency and two stages in audio frequency; and Fig.

i6 shows another modiication in the `arrangement of the tube elements.

We denominate our improved. tube as a four element tube, these elements being respectively the emittin element or filament, (sometimes known as t e cathode) induction plate, anode, and control electrode. In the drawings 1 represents the filament whose eirtremities are connected by the leading-1n wires 2, 3, to insulated terminals 4, 5, respectively, carri'd b the base 6. This base consists of theusuai, cylindrical sheet' metal cup having a globe or evacuated vessel 7, generally of glass, projecting from one end, and 1n its usual form is provided at one side wltha radial stud 8 adapted to enter the slot 9 1n the wall of the socket 10, thereby simultane- 95 ously securing it in the socket and indexing it with the terminals 4, 5, etc., in engagement with suitable companion contacts carried by the bottom of the socket. Inside the globe is formed the usual glass post or press 11 10o through which the leading-in wires project and to which the different elements are attached. The lilament is here shown as supported by a bracket 12 secured in this press.

The induction plate and anode consist of narrow slips of metal 15 and 16 supported, one at each side of the filament, and presented edgewise to the filament and in the same plane therewith. The plate 15 is grounded to the base 6 by the leading-in wire 17 While the anode 16 is connected by the leading-in wire 18 to a contact member 19 insulated at the end of the base, this being the contact member which is ordinarily, in previous systems, known as the plate contact." Outside of and embracing the three elements heretofore described is the control electrode 2() which, in the forni shown in Figs. 1 and 3, comprises parallel spaced portions 21-21 located upon opposite sides of the plates 15 and 16, and outwardly bulged portions 22-22 located opposite the filament. This member is mounted on brackets 23 23 carried by the press and is connected by a leading-in wire 2-1 to that terminal which in some sets is called the grid contact."

ln order to use a tube of this construction in a single circuit regenerator set it is necessary merely to employ a third battery, which we herein denominate the l battery, connected to the end of the present B battery and having its positive pole connected to the socket by a conductor 26 as shown in Fig. 2. The resultingr circuit is portrayed in Fig. 13 wherein the added parts are shown by a heavier line. 30 represents the antenna, 31 a variable condenser, 32 the variable inductive coupler generally used with such apparatus, and 33 the ground connection. One end of the primary of this coupler is connected to the control electrode 20 by means of a connection 34 preferably containing a stopping condenser 35 of extremely small capacity (such as e. g. .00025 M. F.) sometimes known as a grid condenser. The A bat tery is connected between the terminals 4, 5, of the filament. One end of the secondary of the inductive coupler is attached to the anode 16 by way of the point 19, the opposite end of the secondary bein connected to the positive end of the B attery by means of a circuit 36 which contains the receiver R. The negative end of the B battery is connected to the positive end of the A battery; the negative end of the A battery is grounded by way of connection 37; and the negative end of the C battery is oonnec d to the positive end of the B battery, th positive end of the C battery being connected to the plate 15 by way of the conductor 26 and point 6.

There is, therefore, between the two legs ofthe filament a potential equal to that of the A battery which tends to illuminate such filament; between the filament 1 and anode 16 a potential exists equal to that of the B7 battery; between the filament 1 and induction plate 15 a potential exists equal to the combined potentials of the B and C batteries. Thus it' batteries B and C have the same number of cells, the positive potential of the plate 15 is exactly double the positive potential of the plate 16. We have shown the C battery as separate from the B battery, and this is in practice a correct arrangement in some cases, but in other cases we employ onlya single battery having a tap at some point, thereby in eii'ect breaking it into two hatQ teries.

There is no metallic connection between the C battery and the control electrode 20, but the inductive eii'ect of the positive plate 15 upon the control electrode 20 adjacent thereto is to create upon the latter an induced negative charge which constitutes the desired bias and to that extent deflects the negative electrons emitted by the lament and causes them to approach either the highly positive plate 15 or the less positive plate 16. Upon the diminished normal potential of the control electrode 20 thus inductively produced, is superposed the constantly varying potential de rived from the antenna circuit, and this in conjunction with the effect of the coupler causes a varying current to How between the filament and anode under the impulse of the B battery. It will, therefore, be seen that the control electrode 20 has the same functions as the grid in previous systems, and that the A battery and .B battery serve the same function in exactly the `same way as heretofore, the sole purpose of the C battery being to furnish a fixed potential for the inductlon plate 15, and the sole purpose of the induction late 15 to maintain inductively the desiredp normal potential of the control electrode. It is, however, impossible for the potential of this control electrode to become varied either u or down in such fashion as to necessitate a ischarge and no re-ra-diation from the antenna can occur, while incoming signals are received with a maximum of clearness, a minimum of distortion, and great accuracy of elimination of other Wave lengths.

The elements in the tube may assume diierent sha es. For example in Fig. 4 I have shown t e control electrode 20 as made merely of two flat members 20L-20'* spaced upon opposite sides of the plates 15 and 16, these plates being prevented from unduly inuencing the filament by having their interiors coated at 22 with some suitable insulating material. In Fig. 5 I have shown the control electrode as made in four separate segments 20", arranged in pairs on o posite sides of the plates 15 and 16 and space a art at adjacent edges so as not unduly to in uence the filament. In Fig. 6 the control electrode is made of a flattened tube of screen cloth 20, and in this case I have also shown a change l on l LSU control electrode 20 substantially like that shown in Figs. 1 and 3 in combination with plates 15b and 16" of different conformation, made by folding strips of sheet metal into U- shape as illustrated in Fig. 8, the edges being flared apart and formed with serrations 40. `It will be iiotedthat the edges of the plates 15'L and 16a being made of screen cloth will also exhibit much the same serrations, and under certain circumstances these are employed for a special purpose as willbe pointed out hereafter.

In all the foregoing views the control electrode has been located on the outside, although this is not always necessary. In Figs. 9 to 12 inclusive we have shown another form of our improved four element tube in which lthe control electrode is located inside the plates.

In Fig. 9 the filament 1 appears as before but the control electrode consists of a flattened coil 41 of iine wire mounted on suitable posts 42-42 and connected by a leading-in wire 24. with the terminal 25. The plates 15c and 16c consist of channel shaped metal members closely embracing this control electrode and having their open mouths presented towards each other at a slight distance as shown in Figs. 9 and 10. The inductance plate 15c is', as before, rounded to the base y the leading-in wire 1 while the anode 16 is, as before, connected by a wire 18 to the terminal 19. This device can be substituted for the tube shown in Fig. 1 without change of effect, and while we do not propose to limit ourselves by expressions of theory, yet the observed mode of operation is consonant with the hypothesis that the hi h potential C battery acting upon the inuctance plate 15c serves to induce a correspondingly depressed negative potential in the control electrode, thereb maintain the desired bias. lt is possibi7 to vary lie relative sizes of these plates as shown in Fig. 11 at 15" and 16; likwise to arrange them differently, as, for example, in Fig. 12 where the plate 16l is confined to one side of the grid and the plate 15l to the other side. In general and on the score of clearness, loudness, and reliability, accuracy of selectivity and freedom from static and re-radiation, we prefer the form of tube shown in Fig. 1 but illustrate Figs. 9 to 12 inclusive in order to show certain modified forms which are entirely su/ccessful.

In Fig. 16 we have shown another arrangement of parts wherein 1 represents the filament, 41 the control electrode which is supported on a frame/42 as shown in Fig. 9, and 16", 16 represent the inducing plates which are here located inside the grid. The mode of connection and operation is the same as before, the lates 16c being preferably grounded to the ase, and being 1n any case so connected to the high potential battery as to create an induced change on the grid.

In Fig. 14 we have shown the mode of em ploying our improved tubes for amplifying purposes in audio frequency. The parts at the left hand end of the view are identical with those of Fig. 13. The circuit 36, however, instead of being connected directly to a receiver is connected to the primary 50 of an iron core transformer T', a suitable condenser 51 being bridged thereacross to compensate for the inductance thereof. This circuit returns to a point midway the B and C batteries as illustrated in Fig. 13. The mode of connecting the other tubes is, however, quite different. The tube just described serves as a detector and its control electrode is given a normal negative bias.` whereas the control electrodes of the amplifier tubes are maintained at a positive potential. To effect this, the induction plate 15', instead of being connected to the terminal of the B battery is connected to the terminal of the C battery, as, for example, by being grounded to the side of the filament 1 as shown in Fig. 14. This can be effected either inside or outside the tube as will be obvious.

The secondary 52 of the transformer T' is connected between the opposite side of that filament, 1', and the corresponding control electrode 20'; the anode 16 is connected to the primary 53 of a succeeding iron-core transformer T the opposite end of such primary being connected to the end of the B battery. (For convenience we identify the ortions of the battery on opposite sides of the detector head as B and C, although in practice they may consist of only a single battery with an intermediate terminal as shown in Fig. 14.) The filament is illuminated by the A battery in the usual way and the operation of the tube as an amplifier can be explained in different ways: for example, that the control electrode 20 having a positive bias by induction from the plate 15 tends to attract to itself the electrons `forced from the hot filament by the combined effect of the B and C batteries, while the negatively charged plate 15 tends to repel the same, and as the otential of the control electrode 20 varies above and below this normal point by reason of the E. M. F. induced in the transformer, T', a correspondingly varying number of electrons are icked up by the anode plate 16 which then" ow through the coil 53 and back to the B battery in the form of a variable current. Another explanation ascribes a certain measure of condenser effect to the plate 15 with the production of a more definite current in the secondary coil 52` but, whatever the explanation, an augmented current flows in the coil 53 and a telephone receiver if connected there will convert the same ci to the control electrode 20 into sound, or another amplification can be secured in the same Way by attaching the secondary 54, one end to the control electrode and the other end to the filament 1 of yet another tube. lVhen a tube of the same kind is employed it is coupled in the same manner, the anode plate 16l of the tube being connected either to a receiver R or to another transformer. It is not necessary, however, to use a tube of the same kind as other types, makes, or designs of tube can be employed if properly hooked up. Also any one of the tubes herein described can be employed at any point although as a detector our present preference is to use the tube shown in Fig. 1 and for amplifying pur oses that shown in Fig. 7. The serrated e es of the plates 16J and 15b ap ear to exhi it an enhanced controlling elfbct upon the electron flow. This preference is not equal for all circuits. It should especially be noted, however, that in so far as concerns the prevention of reradiation no feed-back to the antenna circuit can occur through one of our tubes even though all the succeeding tubes be of adifferent type.

In Fig. 15 we have shown another and more extensive circuit illustrating a five tube set having two stages of amplification in radio frequency and two stages 1n audio freuency, all the tubes being of our improve t pe. An antenna is grounded at 61 through the primary 62 of a radio frequency transformer. The secondary 63 of the transformer is connected, one end to the negative side of the first filament, 1, and the other end to the control electrode 20 of the first tube, a variable condenser 64 of ro er capacity (say .0005 M. F.) being bridged) across the same. The anode plate 16 is connected b a loop 65 to the mid-point tap of a transfiirmer secondary 70, one end of which is connected to the end of the B battery. The pur ose of this tap is two fold, partly to effect t is conl nection and partly to double the waves as will be shown. The inductance plate 15 is connected to the end of the B battery by way of the primary 67 of the same transformer. The bias thus variations above and below such bias pro duced by the incoming signals, creates a succession of semi waves in the circuit which contains the plate 15, winding 67, B battery, and filament 1; but these are not complete waves since they are created solely by the flow of negative electrons, In oder to fill in the remaining half of the wave form and thus double the power value we employ the transformer Whose mid-point (magnetically) is ,connected to the circuit as shown. In this way the transformer is given a bias the same way as the grid but of opposite sign.

The ends of this secondary winding are connected, one to the filament 1' and the other of the next tube,

produced, coupled with the the inducing as in the case of the preceding tube, and are, as before, bridged by a variable condenser 71, of the same capacity as before. The inductance plate 15 is connected to the transformer winding 72 and thence to the -lend of the B battery; theanode plate 16 is connected to the mid-point tap 73 of the secondary Winding 74 of the same transformer, and also b Way of a variable condenser 75 With the -lside of the filament circuit. The capacity of this condenser may be very small; We have used .0001 M. F. maximum as it is required onlyJgo leak off excessive potential.

Special mention may be made of the three first or radio-frequency transformers. The three should be balanced accurately among themselves, each having the same primary inductance and the same secondary inductance and the mid-point taps being placed at the exact center of inductance. These can be made only by careful measurement with a Wave meter and misbalancing even by an amount of 1A turn is noticeably detrimental.

The two ends of the, secondary Winding 74 are connected, one to the filament 1 of the next tube (which is here connected as a detector) and the other by way of the condenser 76 to the control electrode 20" thereof. The condenser 7 6 may Well have a capacity of .00025 M. F. The winding 74 is alsobridged by a variable condenser 77 the same as condensers 64 and 71. This tube, being used as a detector is connected differently, the plate 16 being joined to the -land of the B battery with the result that the control electrode 20" is given a -f bias. The filament 1 is connected as before; the plate 15 is connected to one end of the primary winding 80 of an iron-core transformer, the opposite end of which is connected to the intermediate tap 81 of the B battery. The added inductance of this primary winding caused by the iron core is offset by a condenser 82, say of .006 M. F. capacity. The operation of this section of the circuit is exactly like that of F ig. 13.

The secondary winding 84 is connected, one end to the control electrode 20 of a succeeding tube and the other end to one side of the lament 1". The plate 16' is connected to the other side of the filament and the plate 15 is connected 'either to a succeeding audio amplifier or to a receiver R; the hook-up and operation being exactly as shown in Fig. 14 no further description is necessary. I have shown the B battery as bridged by a by-pass condenser 90, which may well have a capacity of about .006 M. F. and serves to leak off any undue potential, which might otherwise become built up in the' tubes or parts.

It will be noted that our improved centertap. transformers are intimately linked with connecting the same the C battery shown effect .the same idea practice this 1s effected b to the sockets in place o in Fig. 2, this being in lates of our improved tubes. In

owing to the fact that the B battery in Fi 15 is connected through the transformer. t follows, however, that our improved tubes can be replaced by any of the standard tubes now on the market and the set will continue to operate, not as Well, indeed, as with our improved tubes, but as Well as other sets, the center taps being merely rendered useless by reason of the fact that the sockets are no longer connected to any part of the tube.

We do not, however, limit our improved tubes to use with any of these circuits, nor do We limit these circuits to use solely with our improved tubes (although the combination offers peculiar advantages) nor do We limit ourselves to details of any nature except as speciiically recited in our several claims which are to be construed each independently of limitations contained in other claims.

Except as specifically claimed We do not limit ourselves to the use of a heated filament as a source of electrons but Whenever We have recited an .electron emitting member or a source ot negative electrons We intend to denote all sources, Whether thermal, chemical, or electrical in their nature. Neither do We limit ourselves as regards the pressure or the chemical nature of the gaseous content of the tube, since there are grounds for a belief that under certain conditions of electron emission it may be advantageous to have a substantial amount of gas in the tube although our present preference is to use a heated filament of fairly high emission rate inside a high vacuum. Neither do We restrict this to a radio tube since it is capable of use in telephone and other signaling Work.

Having thus described our invention what we claim is:

l. A radio reception tube comprising the combination with an evacuated vessel of an electron emitting member inclosed therein, tvvo companion electrodes inclosed within said vessel and adapted between them to absorb the electrons emitted by the first eleotrode, a conductive plate supported in induetive relation as regards one of said electrodes and adapted to bind an induced charge thereon, means for maintaining said conductive' plate at a fixed potential of substantial magY nitude, means for conveying the oscillations to be detected and amplified to the electrode having the induced charge, and a receiving circuit containing said electron emitting member and the remaining electrode.

2. A radio reception tube comprising the combination with a container and a metallic base therefor of the type having four insulated contact members in its end, of a filament in said container connected to two ot said contacts, a pair ot' conductive members located inside said container and in absorbing relation to said filament, one of said conductive members being connected to each ot the other contacts, and a fourth member located inside said container in inductive rela.- tion as regards one of said conductive members, said last member grounded to said base.

3. In radio reception apparatus, a tube, a source of negative electrons therein, an electron absorbing member, an electron-controlling member, a conductive member in inductive relation to said controlling member, a B battery, a transformer having a tap leading from the magnetic center of its secondary to said conductive member, the primary being connected, one end to the positive end of the B `battery' and the other end to the electron absorbing member, means tor conveying the oscillations to be detected to the electron controlling member, and reception means connected through said secondary and to the negative end of the B battery.

4. An oscillation detector comprising an evacuated vessel, an electrode inclosed therein, means for heating said electrode, a second electrode inclosed within said vessel, a local circuit having its terminals connected to said electrodes, a conducting member inclosed Within said vessel and located in absorbing relation to said heated electrode, a circuit for conveying the oscillations to be detected to said conducting member, a second conducting member located inside said vessel in inductive relation to said first conducting member, and means for maintaining said last member at a fixed substantial positive potential.

5. A radio reception tube comprising the combination with electron emitting and controlling members and an output electrode, of means for maintaining said output electrode at a potential higher than that ot said electron emitting member, and means for maintaining a bias on said controlling member comprising an auxiliary plate located in inductve relation relative thereto and means for maintaining said auxiliary plate at a potential above that of any of the other tube elements.

6. A radio reception apparatus comprising a tube having therein a cathode, a controlling member, an output electrode, and an auxiliary conducting plate supported inside the actuated space and outside ot the direct path between said emitting memberand output electrode, and means for mamtaming said output electrode at a potential above that of the electron emitting member, and means for maintaining said auxiliary plate at a constant potential above that ot said output electrode.

7. A radio reception apparatus comprising in combination a tube containing an electron emitting member, an electron controlling member and two elect ron absorbing members, two external oscillating circuits, one including said electron emitting and electron controlling member and the other includin said electron emitting member and one o said electron absorbing members, and means for impressing a constant positive potential to the other of said electron absorbing members. In testimony whereof, we herento affix our signatures. l

MYRON J. RITTENHOUSE. OSCAR V. MAURER.

electron absorbing members, and means for impressing n constant positive potential to the other of said electron absorbing members. In testimony whereof, we herento aix our signatures. l

MYRON J. RITTENHOUSE. OSCAR V. MAURER.

CERTIFICATE OF CORRECTION.

Patent No. 1.781.861. Granted November 18, 1930, to

MYRON J. RITTENHOUSE ET AL.

it is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, lines 33 and 43, for the word "inductance" read induction; same page, line 46, for the misspelled word "maintaing" read maintaining, line 47, for "possibi" read possible, and line 49, for "likwise" read likewise; page 4, line 46 and lines 68 and 69, forthe word "inductance" read induction, and line 99, for "and" read end; and that the said Letters Patent should he read with these corrections therein that the same may conform to the record of the case in the PatentOffice.

Signed and sealed this 27th day of January, A. D. 1931.

M. J. Moore,

(sul) Acting Commissioner of Patents.

CERTIFICATE 0F CORRECTION.

Patent No. l,78l,86l. Granted November I8, 1930, to

MYRON J. RITTENHOUSE ET AL.

lt 'is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, lines 33 and 43, lor the word "inductance" read induction; same page, line 46, for the misspelled word "maintaing" read maintaining, line 47, for "possibi" read possible, and line 49, for "lkwise read likewise; page 4, line 46 and lines 68 and 69, for the word "inductance" read induction, and line 99, for "and" read end; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the PatentDffice.

Signed and sealed this 27th day of January, A. D. 1931.

M. J. Moore, (Sell) Acting Commissioner of Patents. 

